No postback while running ASP.NET 1.1 Applications under IIS 6.0

I recently tried to move some old ASP.NET 1.1 web applications (along with some ASP.NET 2.0 apps) from a Windows 2000 server, to a Windows 2003 server. So in effect we were moving applications from IIS 5.x to IIS 6.0.

I noticed a strange behavior for all the ASP.NET 1.1 applications. The issue was these application would not post back any page and so no postbacks were occuring - which basically renders the applications useless. This was noted while using Microsoft Internet Explorer (6.x to 8.x), whereas the same application would work fine if you would use Google Chrome 17.x. I knew this was fishy enough and at some point, some client side script is not working as expected. 

Finally, the solution was to re-install the 1.1 framework/script maps. That was done with the good old "aspnet_regiis -i" command. I was afraid, that would mess up the 2.0 script maps/application, fortunately it didnt.